An internal combustion engine may include a turbocharger compressor or a supercharger compressor to increase engine output. Turbocharger compressor output and mechanically driven supercharger compress output may be linked to engine output because exhaust gases may be required to rotate the turbocharger compressor and because the supercharger compressor may rotate at a speed that is a multiple of engine speed. As such, output of turbocharger compressors and supercharger compressors may not always be aligned with driver demand torque and vehicle operating conditions. One way to overcome the direct linkages between engine output and output of turbocharger or supercharger compressors may be to electrically drive the turbocharger compressor or supercharger compressor during some operating conditions. For example, an electrically driven turbocharger compressor or supercharger compressor may be operated when engine speed is zero to improve direct engine starting. Further, an electrically driven turbocharger compressor may be driven via an electric machine during engine operating conditions when exhaust gas flow is low so that turbocharger lag may be reduced when a vehicle's driver applies an accelerator pedal. As such, electrically driven turbocharger compressors and supercharger compressors may provide benefits that are not available via engine driven compressors. However, electrically driven turbocharges and superchargers may degrade if they are operated at high temperatures for extended periods of time. Therefore, integrated controllers within the electrically driven turbocharger compressors and supercharger compressors may limit output of electrically driven turbocharger compressors and supercharger compressors. This may reduce the possibility of electrically driven turbocharger compressor or supercharger compressor degradation, but it may also disturb engine torque production and vehicle occupants. Therefore, it may be desirable to reduce the possibility of electrically driven turbocharger compressor or supercharger degradation in a way that may be less disturbing to vehicle occupants.
The inventors herein have recognized the above-mentioned disadvantages and have developed an engine operating method, comprising: via a controller, reducing output of an electrically driven compressor that provides air to an engine according to a temperature of a liquid passing through the electrically driven compressor; and reducing the temperature of the liquid via reducing output of the engine via the controller.
By reducing output of an electrically driven compressor that provides air to an engine according to a temperature of a liquid that passes through the electrically driven compressor, it may be possible to reduce electrically driven compressor output while reducing output of an engine so that power reduction by the engine may be smoother than if output of the electrically driven compressor was reduced alone. For example, an engine controller may command a reduction in electric compressor output in conjunction or in cooperation with reducing engine torque via reducing an opening amount of an engine throttle so that the progression of engine torque reduction may be smoothed.
The present description may provide several advantages. In particular, the approach may reduce driveline torque disturbances that are related to operation of an electrically driven compressor. In addition, the approach may be applied to a wide variety of engine configurations. Further, the approach includes control actions to reduce the possibility of degradation of the electrically driven compressor.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.